1. Technical Field
The disclosure generally relates to audio devices, and particularly to an audio device used by a portable electronic device.
2. Description of Related Art
A portable electronic device, such as a mobile phone, commonly includes a built-in speaker to output audio. However, sound volume and quality of the built-in speaker usually is usually insufficient so that an external audio device such as a loudspeaker may be connected to the portable electronic device and output the sound with an increased sound volume and higher sound quality. The external audio device generally has a complex structure which may include a speaker, an amplifier circuit and a power source. Thus, the external audio device is commonly heavy and bulky and inconvenient for the user to carry.
Therefore, there is room for improvement within the art.